在超精密金刚石车削（SPDT）过程中6H-SiC脆性去除时各向异性对变形和裂纹形成的影响。

Effect of anisotropy on deformation and crack formation under the brittle removal of 6H-SiC during SPDT process.

作者信息

Meng Binbin, Li Chen

机构信息

School of Future Science and Engineering, Soochow University, Suzhou 215000, China.

State Key Laboratory of Robotics and System (HIT), Harbin Institute of Technology, Harbin 150001, China.

出版信息

J Adv Res. 2024 Feb;56:103-112. doi: 10.1016/j.jare.2023.04.004. Epub 2023 Apr 13.

DOI:10.1016/j.jare.2023.04.004

PMID:37061216

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC10834810/

Abstract

INTRODUCTION

Monocrystal SiC is representative of the third generation semiconductor materials, the efficient process technology of 6H-SiC wafer have always been a hot topic. Developing a SPDT processing method based on brittle removal mode with controllable surface/subsurface damage is an important approach to solve the processing difficulties of 6H-SiC.

OBJECTIVES

This work aims to analyze the brittle removal process and fully explain the brittle separation behavior and deformation mechanism of 6H-SiC. The micro-scale crack propagation and the effect of anisotropy on crack distribution during machining process are investigated.

METHODS

Large-scale molecular dynamics simulation was used in this work.

RESULTS

Under the condition of brittle removal, shear fracture occurs in the front area of tool tip. Shear plane is high-index surface, independent of slip system. The location of tensile fracture is the cleavage plane of hexagonal system, and the fracture surface is composed of step-like joint planes or perfect plane structures. Cracks with self-healing capability appear in the area behind the tool when the surface to be machined is basal plane. When the surface to be machined is not basal plane, a large number of dislocations or cracks remain in subsurface region. Under brittle removal mode, a large amount of plastic deformation appears as well, and deformation mode is related to processing scheme.

CONCLUSION

The brittle removal behavior of 6H-SiC under SPDT process has obvious anisotropy. Basal plane is more suitable for brittle removal of 6H-SiC without residual damage such as sub-surface cracks. The crack behind the tool generated by cleavage fracture can be repaired by itself. Fracture behavior is not related to dislocation. The processing method parallel to the c-axis can cause the generation of a large number of surface cracks. The (011¯0)/[21¯1¯0] and (112¯0)/[11¯00] mode is the best way to achieve plastic removal of 6H-SiC during SPDT process.

摘要

引言

单晶硅碳化硅是第三代半导体材料的代表，6H-SiC 晶圆的高效加工技术一直是热门话题。开发一种基于脆性去除模式且表面/亚表面损伤可控的单刀双掷（SPDT）加工方法是解决 6H-SiC 加工难题的重要途径。

目的

本工作旨在分析脆性去除过程，并充分解释 6H-SiC 的脆性分离行为和变形机制。研究加工过程中的微观尺度裂纹扩展以及各向异性对裂纹分布的影响。

方法

本工作采用大规模分子动力学模拟。

结果

在脆性去除条件下，刀具尖端前方区域发生剪切断裂。剪切面为高指数面，与滑移系无关。拉伸断裂位置为六方系解理面，断口由阶梯状结合面或完美平面结构组成。当待加工表面为基面时，刀具后方区域会出现具有自愈能力的裂纹。当待加工表面不是基面时，亚表面区域会残留大量位错或裂纹。在脆性去除模式下，也会出现大量塑性变形，且变形模式与加工方案有关。

结论

6H-SiC 在 SPDT 加工过程中的脆性去除行为具有明显的各向异性。基面更适合 6H-SiC 的脆性去除，且不会产生诸如亚表面裂纹等残留损伤。解理断裂产生的刀具后方裂纹可自行修复。断裂行为与位错无关。平行于 c 轴的加工方法会导致大量表面裂纹的产生。(011¯0)/[21¯1¯0] 和 (112¯0)/[11¯00] 模式是在 SPDT 加工过程中实现 6H-SiC 塑性去除的最佳方式。